Dental plaque is present to some degree, in the form of a film, on virtually all dental surfaces. It is a by-product of microbial growth, and comprises a dense microbial layer consisting of a mass of microorganisms embedded in a polysaccharide matrix. The microorganisms present in plaque are mainly coccoidal organisms, particularly in early plaque, which, in the mouths of some persons at least, change to filamentous organisms after a few days. Plaque itself adheres firmly to dental surfaces and is removed only with difficulty even through a rigorous brushing regimen. Moreover, plaque rapidly reforms on the tooth surface after it is removed.
A wide variety of microorganisms are found in the oral cavity, and among these are gram-positive anaerobic rods associated with the development of plaque such as Corynebacterium, Nocardia, Neisseria and Streptococci, such as S. mutens, S. bovis, S. salivarius, and gram-positive streptococci of the genus Peptostreptooccus (See Robert J. Fitzgerald in "The Alabama Journal of Medical Sciences" Volume 5, No. 3, July, 1968, pp. 241-242).
In addition to the aforementioned microorganisms, there is also present in plaque relatively small amounts of other substances such as salivary proteins, carbohydrates, epithelial cells and leucocytes. These organisms play a key role in the etiology of plaque. The bacterial organisms associated with plaque formation produce a capsular material which apparently causes the cells of the organism to adhere to each other, holding the plaque together and allowing for further growth. For example, one of the capsule forming bacteria which occurs in large numbers in early plaque is Neisseria sicca.
Plaque may form on any part of the tooth surfaces, and is found particularly at the gingival margin, in cracks in the enamel, and on the surface of dental calculus. As discussed in greater detail below, the danger associated with the formation of plaque on the teeth lies in the tendency of plaque to build up and eventually produce gingivitis, periodontitis and other types of periodontal disease, as well as dental caries and dental calculus.
More specifically, dental plaque is a precursor to the formation of the hard crystalline buildup on teeth referred to as dental calculus. Both the bacterial and the nonbacterial components of plaque mineralize to form calculus, whicn comprises mineralized bacteria as well as organic constituents, such as epithelial cells, live bacteria, salivary proteins, leucocytes, and crystals of substances having molecularly bound calcium and phosphorus, e.g., hydroxyapatite, 3[Ca.sub.3 (PO.sub.4).sub.2 ]Ca(OH).sub.2, octacalcium phosphate, Ca.sub.8 (HPO.sub.4).sub.2 (PO.sub.4).sub.4.5H.sub.2 O, brushite, CaHPO.sub.4..sub.2 H.sub.2 O, and whitlockite, which is considered to have the formula beta-Ca.sub.3 (PO.sub.4).sub.2. Dental plaque and, hence, calculus are particularly prone to form at the ginqival margin, i.e., the junction of the tooth and gingiva. The buildup of plaque at the gingival margin is believed to be the prime cause of gingivitis and other periodontal disorders.
Regular tooth brushing with a conventional dentifrice for some persons greatly retards or even prevents the accumulation of significant amounts of plaque and calculus. For other persons, however, plaque builds up rapidly even with regular brushing, which, in turn, leads to the formation of calculus, caries, and presents the danger of periodontal diseases. Removal by a dentist is currently the only safeguard against serious gingival inflammation caused by the accumulation of significant amounts of of plaque in some individuals. It is widely recognized in dentistry that a rigorous brushing regimen alone for many individuals will not prevent the formation of significant amounts of plaque.
Mouthwashes are employed in conventional regimens of oral hygiene. However, conventional mouthwashes serve primarily to sweeten the breath, are formulated for that purpose, and are believed not to function in any significant way to loosen or remove plaque from the dental surfaces. Moreover, since the user typically does not employ a mouthwash expressly for the purpose of cleansing the teeth of plaque, mouthwashes are not routinely used immediately prior to brushing as a way of rendering plaque and/or calculus more amenable to removal during the subsequent brushing process.
There is, therefore, a definite need in the art for an oral hygiene composition which, when used alone, or in conjunction with a regular tooth brushing regimen, renders the plaque present on the dental surface more susceptible to removal during a subsequent brushing regimen employing a conventional dentifrice.
In view of the foregoing, it is an object of this invention to provide an improved dental rinse which has a detersive effect upon plaque, and which functions to loosen the plaque present on dental surfaces, and thereby to aid in the reduction of caries formation, and to deter the development of calculus and oral diseases associated with excessive plaque formation such as gingivitis and periodontitis.
It is also an objective of this invention to provide an improved method of dental hygiene, and for removing, loosening and retarding the further development of plaque on dental surfaces.